In practice, various types of a cleaning device for cleaning surfaces are known. A well-known example of such a cleaning device is a vacuum cleaner, which is capable of removing dust and dirt particles from surfaces like floors under the influence of a suction force. Another example is a device which comprises a head having an open side for facing surfaces to be cleaned, and at least one brush for contacting surfaces to be cleaned, which is rotatably arranged in the head. The present invention relates to this type of cleaning device, which may comprise means for realizing a suction force at the head, like a vacuum cleaner, but which can also be realized without such means.
The brush of the cleaning device is provided with a plurality of brush hairs. It is possible for these brush hairs to be extremely soft and flexible. For example, the brush hairs can have a linear mass density which is lower than 150 g per 10 km. In such a case, a cleaning action of a surface is not performed by scrubbing the surface, as may normally be expected when a brush is used, but by putting the brush hairs alternately in and out of contact with the surface during rotation of the brush. In particular, during one revolution of the brush, the brush hairs remove particles and/or liquid droplets from a soiled surface on the basis of the fact that the particles and/or the droplets adhere to the brush hairs, or are at least pushed from their initial place by the brush hairs, and fling away the particles and/or the droplets when they reach a position in which they are free from contact to the surface and in which they can be fully outstretched. In the head of the cleaning device, in which the brush is arranged, there are means for receiving the particles and/or the droplets, and for possibly transporting the particles and/or the droplets towards a space where they are collected. The cleaning device may be equipped with means for realizing a suction force at the head, for example, by creating a vacuum, in order to direct the particles and/or the droplets in a desired direction once they are released from the brush hairs.
In order to have an effective process of flinging away particles and/or droplets which have been removed from a surface, the rotation of the brush needs to take place at a certain angular velocity. The angular velocity of the brush may be chosen to be such that an acceleration at tips of the brush hairs can be higher than 3,000 m/sec2 at some point, which is the case when the angular velocity is at least 6,000 revolutions per minute, and a diameter of the brush is in a range of 20 to 80 mm when the brush hairs are fully outstretched, for example.
It is possible for the cleaning device to supply a cleaning liquid to the rotating brush in order to promote the adherence of particles to the brush hairs and/or to realize an additional cleaning effect on a surface to be cleaned, but this is not necessary. In any case, when the cleaning device having at least one brush as mentioned is used, it happens that the head in which the brush is arranged gets contaminated with the particles and/or the droplets which are picked up by the brush hairs and released inside the head. As a consequence, a user of the cleaning device is compelled to clean the head before storing the device. This is an unfavorable aspect of the use of the device, as cleaning the head requires a flushing action of the head, which is not easy to handle, and is quite bothersome.
JP 2005 211426 discloses a cleaning device comprising two cleaning tools, namely a rotatably arranged brush and a rotatably arranged adsorption sheet roller. The cleaning device is combined with a fixed station. When the cleaning device is put in place on the fixed station, washing of the brush and the adsorption sheet roller is performed. In particular, an upper surface of the fixed station is provided with a crevice for receiving the brush and a crevice for receiving the adsorption sheet roller. A cleaning liquid is supplied to the crevices by means of a pipe system. By rotating the brush and the adsorption sheet roller, the brush and the adsorption sheet roller are washed by the cleaning liquid.